> Don't believe that a self driving car changes much beyond who is driving the car
Except everything. Current cars have one occupant a high percentage of the time. That occupant drives the car. Change that and every design parameter changes.
I doubt this. The American car (distinct from cars in general) is not only a utilitarian tool but a cultural artifact. For huge portions of the country it is the manifestation of freedom - especially now that we've demolished all of our urban areas in favor of freeways and strip malls. Look at American culture and you'll see that personal car ownership is intrinsically associated with freedom, coming-of-age, and a huge host of cultural values that Americans take very seriously.
If you think making driverless cars is going to suddenly tilt us away from single-occupant SUVs and into little self-driving pods (Minority Report style), IMO you're sorely mistaken. At best we're going to get SUVs without a steering wheel. Cars will not get substantially smaller without regulatory intervention, people will continue to own personal automobiles, and they will still have more seats than are needed 99% of the time.
Driverless cars will be great, but I think you're severely overestimating their impact on car design/ownership/usage patterns. I know it's popular to imagine a society where people stopped owning cars, where cars are always right-sized for the situation, where cars show up on demand and parking lots made obsolete, etc etc, but that's a 1950s Popular Mechanics style of sci-fi pipe dream.
It does seem kind of plausible. Right now you need a car for everything. To get to work, to buy groceries or anything else from a store, to get to any kind of recreation, etc.
Now suppose there exists an autonomous electric taxi that you can hail from your phone and use to get from one end of the city to another for around $1. You no longer need a car for anything but getting to work. Rush hour is the peak demand so the price of a ride during rush hour would be prohibitive for commuting.
But the same reason the car operators can't justify buying more cars just for rush hour is the same reason commuters won't want to do it. Once commuting is the only reason you own a car you start looking for housing and employment near functioning mass transit. Which is going to bring people back into the cities. And once you do that and people give up owning a car the rest of it follows.
For example, more than 50% of NY households don't own a car[1]. It's easy to argue that NY is a special case, but with 8 million people it's a very large special case. The thing is, there are a lot of special cases[2] that aren't as extreme as NY but in aggregate add up.
[1] http://en.wikipedia.org/wiki/Transportation_in_New_York_City...
[2] http://en.wikipedia.org/wiki/List_of_U.S._cities_with_most_h...